Adhesive-backed plastic tile is commercially available as a convenient substitute product for the conventional plastic tile, in which the adhesive is manually applied to the wall, and then the tile is manually applied to the adhesive-coated wall. A very substantial saving in labor and time is achieved by initially manufacturing the plastic tile with the adhesive already applied, so the user can simply remove a backing layer and install the tile on a surface without the need for applying an adhesive layer in a separate step.
However, particularly with wall tile, there has been no convenient adhesive which can be effectively applied to tile, other than inexpensive, light-weight vacuum-formed tile, capable of delivering desirable adhesion characteristics so that the tiles do not fall off of the wall after a period of time. In particular, the tile adhesive systems of the prior art have exhibited the undesirable characteristic of losing cohesive strength, due to the migration of plasticizer from the plastic tile to the adhesive. As a result of this, it has hitherto not been feasible to market adhesive-backed plastic wall tile, particularly in which the adhesive is of the "hot-melt" type. This latter type of adhesive is particularly unable to maintain adequate cohesive strength for use with heavy, high quality wall tile, because of the problem of plasticizer migration into the adhesive.
Tile with acrylic latex-type adhesive is less susceptible to a degradation of physical properties due to the migration of plasticizer, but acrylic latex adhesives are disadvantageous for other reasons. For example they require a significant drying time during manufacture, which results in a significantly lower manufacturing line speed and production rate.
Accordingly, there is a clear need for a hot-melt adhesive-backed plastic tile system in which the adhesive layer does not degrade to such a degree that it lacks adequate cohesive strength to support the tile on a vertical surface such as a wall.
The invention of this application provides such an adhesive-baked plastic member, typically a plastic wall tile, utilizing a plasticizer and a hot-melt adhesive system which results in a significantly reduced degradation of physical properties of the adhesive upon storage, so that commercially acceptable, adhesive-backed plastic wall tile and the like can be produced.